docs: def _get_role(rolename):
      """Reads and parses a file containing a role"""
      path = os.path.join('roles', rolename + '.json')
      if not os.path.exists(path):
          abort("Couldn't read role file {0}".format(path))
      with open(path, 'r') as f:
          try:
              role = json.loads(f.read())
          except ValueError as e:
              msg = "Little Chef found the following error in your"
              msg += " {0}.json file:\n  {1}".format(rolename, str(e))
              abort(msg)
          role['fullname'] = rolename
          return role